Tellurium
A copper-refining by-product that makes cadmium telluride solar panels and thermoelectric coolers, produced mostly in Chinese refineries.
Tech & minor metals · No. 41
- US critical 2025
- India critical 2023
- HHI 6,242 · highly concentrated
Most tellurium is scraped from the sludge left when copper is refined, and 70% now ends up in solar panels.
Chart: Illustration: Tellurium
Where it comes from
Chart: Map of where it comes from
Tellurium is almost never mined for itself. Over 90% comes from the slimes left when copper anodes are electrorefined; the rest from lead skimmings and smelter dusts.
Three things to know
- More than 90% of tellurium has come from anode slimes, so copper produced by leaching lets its tellurium slip away uncaptured.
- Bismuth telluride, the best thermoelectric at room temperature, puts thermoelectric devices second with about 15% of 2025 use.
- World output doubled from 459 t in 2020 to 958 t in 2024, according to World Mining Data.
The journey
- 1 Copper orePorphyry ore with traces of tellurium
- 2 AnodesConcentrate smelted into copper anodes
- 3 Anode slimesResidue left by electrorefining copper
- 4 Copper tellurideSlimes treated to an intermediate
- 5 Refined telluriumHigh-purity metal, 5N or better
- 6 ProductsCdTe solar modules and thermoelectric devices